Dynamical analysis of maternal heart rate variability in predicting spontaneous premature labour

The aim of this work was to assess the prognostic value of the heart rate variability (HRV) in pregnant women for the early prediction of spontaneous premature labour (PL). We have studied spectral, nonlinear and statistical measures of HRV in 54 women with PL and 88 healthy women with matched age, parity and body weight. Analysis of HRV was performed by the computer processing of 256 successive cardiac intervals at each step of the analyses: rest, arithmetic task and moderate hyperventilation. The mean gestational time at the moment of exam was 20 weeks (from 16 to 24 wks). It was shown that detrended fluctuation analyses (DFA) turned out to be the most sensible predictor of PL. Detection of a diagnostic sign depends on the condition of the autonomic disbalance, either sympathetic (S) or parasympathetic (PS) prevalence type, and also requires exposure to moderate hyperventilation (HV). Decrease of DFA against HV was observed in 71.4% of S subgroup with PL and only in 21.4% of S control (p = 0.005). Vice versa, increase of DFA was distinct in 63.3% of the PS subgroup with PL and in 25.9% of the PS control (p = 0.017). We conclude that prediction of premature labour using dynamic HRV analysis with loading respiratory probe is effective in at least 75% of women in midpregnancy.